JPH0967955A - Beam vibration controlling structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent occurrence of the worst situation by furnishing an opening through removal of a web in the central part of a beam, admitting a shearing deformation of the opening caused by a horizontal force of earthquake, and allowing a damper and a lever to absorb the seismic energy by their deformation. SOLUTION: The web 2 in the central part of a beam is removed and an opening 10 is provided. The base end is supported by flanges 3' remaining over and under the opening 10 and the tip 31 of a lever 30 is coupled with a damper 20. With a seismic input a relative displacement is generated in the end parts of the beam, and the opening 10 with sunk rigidity goes in a shearing deformation. In the case of fine tremor of earthquake, the lever 30 moves in linkage with the flanges 3' to cause deformation of a viscoelastic damper 20 to result in damping of the deformation stroke of the opening 10. In the case of a small/medium size of earthquake, the lever 30 is deformed elastoplastically to result in damping of the deformation stroke of the opening 10. In the case of large earthquake, the top surfaces of stoppers collide with each other to restrict further shearing deformation of the opening 10, so that the opening 10 pill not crush but the two ends of the beam yield to absorb the vibratory energy.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a beam damping structure,
More specifically, by removing the web in the center of the beam and providing an opening, shear deformation of the opening due to the horizontal force response of the building is allowed, and resistance is applied while following the shear deformation stroke of the opening. The present invention relates to a structure in which a beam is used to attenuate input vibration energy to a building by incorporating a damper into the beam.

[0002]

2. Description of the Related Art Conventionally, as a passive vibration control structure in a building, although a base isolation structure having a base isolation layer and a damper structure having a damper on a multi-story wall have been generally adopted, All of these structures have drawbacks such as many restrictions imposed on architectural design, and in recent years, a beam damping structure in which a damper is built in a beam has been proposed as a structure without such drawbacks.

In this beam damping structure, as schematically shown in FIG. 8, a beam 1 for a horizontal force is formed by cutting out a web 2 between upper and lower flanges 3'in a central portion 1'of the beam 1 to provide an opening 10. By lowering the rigidity of the central portion 1 ', the opening 10 is sheared vertically due to the horizontal force response of the building, and the opening 10 is actuated by relative displacement in the vertical direction due to the shear deformation. Damper 90 with opening 1
It is built into 0.

[0004]

However, in the above-mentioned beam damping structure, since a large-scale damper cannot be incorporated in the opening, it is possible to effectively perform the damping function against small and medium-sized earthquakes exceeding the capacity of the damper. In addition, in the case of a large earthquake, it is expected that the beam will be greatly deformed from the opening and the frontage of the building will be collapsed.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a beam damping structure capable of effectively coping with not only minute vibrations but also small to large earthquakes.

[0006]

The beam damping structure according to the present invention is based on an opening formed by removing the web in the central portion of the beam and flanges remaining above and below the opening as means for achieving the above object. Lever members whose end portions are supported and which extend to both the left and right end portions of the beam on both the front and back sides of the web,
The tip end of these lever members and a damper means interposed between the web of the portion facing the tip end, and a stopper member provided on the flange of the opening,
The vertical shearing deformation of the opening due to the horizontal force response of the building is allowed, and the lever member is interlocked with this shearing deformation to expand the shearing deformation by the levering effect so that the damper works effectively. In the structure, when the horizontal force is small, the damper means operates against the shear deformation expanded through the lever member, and the horizontal force exceeds the capacity of the damper means. If the lever member is elastically deformed while taking a reaction force to the flange,
When the horizontal stroke is a large earthquake that damps the deformation stroke of the shear deformation and exceeds the yield point of the opening flange, the stopper member defines the limit of the shear deformation to prevent the collapse of the opening. The feature is that it is prevented.

Here, as the damper means, known viscoelastic dampers, oil dampers, elasto-plastic dampers, friction dampers and the like can be used, but viscoelastic dampers which are easily mounted are most preferable.

As the lever member, it is possible to use a rod-shaped steel material capable of transmitting a minute shear deformation of the opening to the damper means and having a strength (yield point) lower than that of the main structure of the beam.

Further, the elasto-plastic deformation means the elastic deformation of the lever member to a degree slightly exceeding the limit of the capacity of the damper means (generally defined by a stopper or limiter) and exceeding this elastic limit. This is a plastic deformation of the lever member.

Furthermore, the stopper member is a steel material arranged so as to prevent shear deformation exceeding the allowable range of the opening.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic front view showing an H-steel beam 1 having a structure according to the present invention. In FIG. 1 and FIG. 4, a viscoelastic damper 20 as a damper means is represented by a symbol for convenience. ing.

The present structure has an opening 10 formed by cutting out the web 2 in a rectangular shape in the central portion 1'of the beam 1, and a total of two portions installed on the front and back sides of the web 2 near the left and right ends 1 "of the beam 1, respectively. A base end portion 32 is supported by one of the four viscoelastic dampers 20 and a portion (flange 3 ′) that remains above and below the opening portion 10 of the flange 3, and a tip portion 31 is connected to the damper 20 for a total of four levers. The member 30 and the stopper member 40 fixed to the flange 3 ′ are provided, and the base end portion 32 of the lever member 30 may be indirectly connected to the flange 3 ′ via the stopper member 40.

As shown in FIGS. 2 and 3, the viscoelastic damper 20 has a viscoelastic body 21 interposed between the tip portion 31 of the lever member 30 and the portion of the web 2 facing the tip portion 31. Although not shown, the damper 20 is provided with a limiter that defines the elastic limit of the viscoelastic body 21. This limiter can also be achieved by hitting the flange with the end of the lever member when the lever member has a plate shape as shown in FIG.

As the viscoelastic body, the trade name "VEM" is used.
1140 "(made by Sumitomo 3M Ltd., viscoelastic body)
Was used.

The lever member 30 is capable of displacing integrally with the flange 3'of the opening 10 to operate the damper 20, and has a strength lower than that of the main structure (2, 3) of the beam 1. It is made of plate steel.

The stopper member 40 has a predetermined height from each of the upper and lower flanges 3'to the inside of the opening 10 (a height at which they abut against each other due to shear deformation of the opening 10 during a large earthquake. See FIG. 7). With the top surface 41 protruding only
It is made of a box-shaped steel material having strength equal to or higher than that of the main structure of the beam 1.

Next, the operation of this structure will be described.

When a horizontal force is applied to a building (not shown) incorporating the beam 1 by an earthquake or a strong wind, a relative displacement in the vertical direction occurs between the left and right end portions 1 "of the beam 1, which lowers the rigidity. The opening 10 is sheared and deformed in the vertical direction, and this deformation strokes from one of the vertical directions to the other.

When the horizontal force on the building is small, the shearing deformation of the opening 10 is also small as shown in FIG. 4, and at this time, the lever member 30 interlocks with the flange 3'and the space between the flanges 3 is increased. The viscoelastic damper 20 is operated while swinging.
That is, the viscoelastic body 21 of the damper 20 attenuates the deformation stroke of the opening 10 by viscous resistance while deforming as shown in FIG.

In the case of a small-to-medium earthquake in which the horizontal force applied to the building exceeds the capacity of the damper 20, as shown in FIG. 6, the lever member 30 applies a reaction force to the flange 3 via the damper 20 with the limiter functioning. Swing between flanges 3,
It deforms elastically and reduces the deformation stroke of the opening 10.

The structure can be reused by replacing the lever member 20 after the earthquake.

The horizontal force applied to the building is the opening flange 3 '.
In the case of a large earthquake that exceeds the yield point, the stopper members 40 bring the top surfaces 41 into contact with each other to limit further shear deformation of the opening 10, as shown in FIG. Therefore, the opening 10 is not crushed, and both ends 1 ″ of the beam 1 yield and absorb the input vibration energy.

[0024]

As described above, in the beam damping structure according to the present invention, the damper means through the lever member is used in the case of a slight vibration, and the elastic member of the lever member is elastically deformed in the case of a small or medium earthquake, respectively. The input vibration energy to the beam can be attenuated, and in the case of a large earthquake, the stopper member can prevent further deformation of the opening and prevent the worst case such as the frontage being crushed.

[Brief description of drawings]

FIG. 1 is a schematic front view showing a beam damping structure according to the present invention.

FIG. 2 is a cutaway front view showing the vicinity of the left end portion of the beam.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is an explanatory diagram of the present invention at the time of slight vibration.

5 is a cross-sectional view of the viscoelastic damper in the state of FIG.

FIG. 6 is an explanatory diagram of the present invention at the time of a small or medium earthquake.

FIG. 7 is an explanatory diagram of the present invention at the time of a large earthquake.

FIG. 8 is a schematic explanatory view showing a conventional beam damping structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Beam 1'Center part 1 "End part 2 Web 3,3 'Flange 10 Opening part 20 Viscoelastic damper 21 Viscoelastic body 30 Lever member 31 Tip part 32 Base end part 40 Stopper member 41 Top surface

Claims (1)

[Claims] 1. A base end is supported by an opening formed by removing a web in a central portion of a beam, and flanges remaining above and below the opening, and both sides of the web are provided near the left and right ends of the beam. A lever means, a damper means interposed between the tip portions of these lever members and the web at a portion facing the tip portion, and a stopper member provided on the flange of the opening portion. In order to allow shear deformation in the vertical direction of the opening due to the horizontal force response of the building, and to interlock the lever member with this shear deformation, the shear deformation is expanded by the lever effect and the damper effectively acts. If the horizontal force is very small,
By the actuation of the damper means against the shear deformation expanded through the lever member, and when the horizontal force is a small earthquake that exceeds the capacity of the damper member, the lever member reacts with the flange. By elastically plastically deforming each of them, the deformation stroke of the shear deformation is damped, and further, in the case of a large earthquake in which the horizontal force exceeds the yield point of the opening flange, the stopper member causes the shear deformation. The beam damping structure is characterized in that the upper limit is specified to prevent the opening from being crushed.